Air cleaner



Patented Dean, 1934 AIR CLEANER William H. Schu to Donaldson lz, Minneapolis, Minn Company, Inc.,

assignor St. Paul, Minn., a

corporation of Minnesota Application June 13, 1932, Serial No. 616,860

1 Claim.

My present invention relates to air cleaners such as are used in connection with internal combustion engines and provides a simple and highly eilcent dust intercepting screen which,

When properly associated with an underlying oil well and with an air conduit in which latter it is interposed, will cause the oil to spread out in a nlm over its inclined surfaces so as to intercept and wash the dust back into the oil well.

Generally stated, the invention consists ofthe novel devices, combinations of devices hereinafter described and dened in the claims.

The improved screen in its preferred form shown in the drawing has been especially designed for application in an air cleaner of the type disclosed and claimed in application of Frank A. Donaldson entitled Air cleaner" filed of date May 26, 1932, S. N. 613,603 which has matured into Patent Number 1,926,841 dated Sept. 12, 1933.

In the accompanying drawing, which illustrates the invention, like characters indicate like parts throughout the several Views.

Referring to the drawing:

Fig. 1 is a vertical axial section throughan air cleaner of the type above indicated and showing one form of the intercepting screen; and

Fig. 2 is a view corresponding to Fig. 1 but illustrating a slightly modified form o f the screen.

Referring rst to the construction illustrated in Fig. 1. The numeral 3 indicates a receiving end' portion of a carburetor, not shown. The outer shell or casing of the air cleaner illustrated is made up of two sheet metal sections 9 and 10, and the air cleaner outlet tube 11 of the cleaner is in the form of a cylindrical tube axially extended downward from within the casing and telescoped onto the upper end of the 40 carburetor air intake 3.

Near its upper end the air outlet tube 11 is provided with a rigidly secured outstanding annular rest flange 12, and rigidly secured to the upper end of said tube 11 is a spider-like bracket 45 13 which, for a purpose that will presently appear, is provided with an axially located upwardly projecting threaded bolt 14 equipped with a thumb nut 15.

'Ihe bottom of the lower case section 9 is formed to provide an annular oil well 16 from the inner edge of which a sheet metal skirt 17 extends upwardly into the case. The skirt 17 is concentrically spaced from the tube 11 and its upper end is contracted to form an inwardly projecting annular flange 18 that is seated on'the rest flange 12. Near its .flanged upper end, the skirt 17 is provided with a plurality of air passages 19.

The upper section 10 of the casing, at its lower edge, is detachably telescopedgonto the upperedge of the lower section 9. The top of the casing 10 is in the form of a head lthat closes the top of the casing. Secured to and depending from the head 108L is a cylindrical sheet metal skirt 20 that is provided with an inc5 Wardly projecting annular ange 21 seated on the rest ilange 12, a pliable gasket 22 as shown being interposed between the same and said rest flange. That portion of the skirt 20 that is below the ange 21 is concentrically spaced from and outwardly of the skirt 17. The skirt 20 extends down close to the surface of the oil y contained in the annular oil well 16 and divides the casing into two chambers a and b. The skirt 17 forms between the clean air outlet tube 11 and the skirt 20 an annular air intake conduit that extends vertically upward to the air ports 19 and from thence vertically downward to or approximately to the surface of the oil. The importance of this will later appear. In the extreme upper portion of the skirt 20, above the flange 21, are large air outlet ports or passages 23.

The lower section 9 of the casing is directly supported from the rest flange 12 through the skirt 17. When the two case sections 9 and 10 are telescoped together the bolt 14 will be passed through an axial bolt passage in the top of the head 10a, and when the nut 15 is applied, as shown in the drawings, only two case sections will be firmly held together and rmly clamped to and supported from the rest flange 12. The structure so far specifically described is, as above indicated, that illustrated in the co-pending application of said Frank A. Donaldson, led of even date herewith;

My improved screen, as here illustrated, is designed to be placed in the annular compartment b. This screen is therefore of annular form. As shown, it is made as a single or selfcontained element capable oi being removed and replaced. The complete screen is made up of a plurality of annularly corrugated annular or tubular screen elements or sections stacked together in alternately reversed relation with the apexes of their corrugations in contact and their oblique surfaces in alignment. Preferably the annular elements are rectangular in cross section but may deviate considerably in form. The highly important novel feat-ure is, however, 110

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found in the fact that all surfaces of the tubular screen elements or sections have downwardly inclined walls so that the oil in runring downward will spread over the screen and form oil films across the openings of the screens and through which films the air must pass. The manner of making up the tubular elements may vary and the arrangglent pftubes may vary. is illustrated in Fig. 1,'the complete screen is made up of a plurality of tubular annular screen elements 24 thatI are rectangular in cross section.

In practice, I have frequently found it desirable to make up the filter of a multiplicity of screen elements which, instead .of being soldered or permanently yconnected are looselyplaced or piled in contact, one above the other. In fact, the screens illustrated may be assumed to be made up of channel-shaped screen elements loosely placed together in alternately reversed relation.

'iAsgroupedJniFigul, the tubular screen sections 242 are so lassembled that all of the walls of said sections, except the outside walls, are common to adjacent connected sections. Furtherrnore', itis important to note that the walls or connected tubes' are aligned obliquely so that theoil `thrown onto the inclined screen surfaces will runlfreelyzdown. to` connected surfaces of the-inclined screen sectionsl The screen elements th'at 'make up the sections 24 may be prirnnrilyvformed in variousdiierent ways and thereafter 'connected in the Aarrangement illustratedlor insaffsimsllar arrangement wherein the surfaces-of `iihetubular .-screens are inclined.

` The lower-portion of the screen made up of sections 241 will be positioned close to the surface of-'the -oil y; As is indicated, this screen is preferably readily removable and replaceable. The'downward movement thereof in the casing may be limited 'in'various different ways, but as shc'wn, is limited by a stop bead 25 pressed inward'from an extension flange 10b, which, in the@ arrangement illustrated, is soldered, welded nr "otherwise secured to and constitutes the lower-endportion ofthe upper case section 10.

@The construction illustrated in Fig. 2 is like that; Villustrated-.in Fig. 1,A except that the cornposite screen is made up of a plurality of endless tubular. screen tubes 24a arranged in a single vertical coiumn with the ridges of vertically aligned tubes- .joined 'so that the inclined walls orthe connected Atubesare continuous in the same inclined lines. Naturally, the screen sections' 24 are of greater cross-sectional diameter than 'are the screen sections 24.

' The screen structure illustrated in Fig. 1 has a' much larger screen surface than that illustrated in Fig. 2 and is, therefore, more efficient in'its dust-collectivity and air-cleaning action. Therrtubular rectangular screen sections 24e may be formed in different ways but preferably will be formed by connecting by soldering or otherwise to contacting edges of reversely bulged endless screen channels.

VUnder suction or partial vacuum produced in the-clean air` outlet tube 11, from the carburetor of' an engine (when the device is used as Van air cleaner for'engines) dust-laden air will be 'drawn-primarily'in an upward direction through the annular air channel formed between the tube 11 and skirt 1'7, and from thence outward through ports 19 anddownward to the oil through the annular channel formed between the skirt 17 `and 20. The air will be directed with considerable velocity against the surface of the oil y and much of the dust carried by the air will be directly taken up by the oil. The oil will, however, be quite violently agitated. producing a sort of a foam which will be carried upward with the air through the numerous surfaces of the screen. The screen should be so designed and proportioned that no oil will be carried completely through the uppermost screen section. The oil carried onto the screen surface will, through the action of gravity, flow downward. over the inclined surfaces thereof, form oil films over the screen openings, through which the -air must pass, on its Way through ports 23 to the clean air outlet tube 11. There will, therefore, be va continuous upward carrying of oil onto the screens and a continuous downward or return flow of oil that is picked up and carries the dust from the air. The downwardly running oil will spread in two directions, to wit: toward the outer and toward the inner walls of the annular chamber that contains the screen and the dust-laden oil will, therefore, return to the body of the oil in the well 16 by routes that closely follow the inner walls of the screen-containing chamber b.`

Obviously, the air must pass through many oil films before it completely passes through vthe screen and when it has passed the screen, the. air will be substantially one hundred per cent clean or free from dust or foreign particles.

By reference particularly to Figs. 1 and 2, it will be noted that the screen is made up of a multiplicity of corrugated woven wire screen elements and that the total surface area ofveach screen element has greater area than the crosssection of the air passage in which it is inter-r posed. Hence, when the said screens are quitev obliquely extended and made of fine wire, as illustrated in the drawing, the total air passage through a screen element will exceed the crosssectional area of the air passage. This important result is one that can be obtained only by the use of woven Wire screens assembled with their surfaces oblique to the line of passage of the air and in a sectional relation that produces corrugations in the assembled screen. By placing the corrugated screens in non-nesting relation with their apexes in contact, air spaces are formed between the screens and the inclined surface of one screen delivers to the reversely inclined surface of an adjacent screen.

The eiciency of this screen in the arrangement illustrated in the drawing and in various other modified arrangements, has been veryv thoroughly demonstrated in practice, as to general results, and by laboratory tests as to exact results.

What I claim is:

In an air cleaner having an oil well, a cylindrical oil distributing dust intercepting screen having an axial passage therethrough and being made up of a plurality of annularly cor.- rugated annular screen elements, said annular screen elements being stacked together in alternately reversed relation with the apexes of their corrugations in contact and' their inclined surfaces in oblique alignment.

WILLIAM H. SCHULZ.

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